@lines = <LOGFILE>;

foreach $line (@lines) {
if ($line != m/\s/) {
# regex to turn dates into epoch
($dd, $mm, $yy, $hh, $mt, $tt, $tdd, $tmm, $tyy, $thh, $tmt, $ttt) = $line =~ /(\d+)-(\d+)-(\d+)\s(\d+):(\d+)\s(am|pm)-(\d+)-(\d+)-(\d+)\s(\d+):(\d+)\s(am|pm)/;

if ($tt == 'pm') {
$hh = $hh + 12;
}

if ($ttt == 'pm') {
$thh = $thh + 12;
}

$t_from = timelocal(0,$mt,$hh,$dd,$mm,$yy);
$t_to = timelocal(0,$tmt,$thh,$tdd,$tmm,$tyy);
$s_elapsed = $t_to - $t_from;

...